Expanding rock-drill



(Model.)

J. GREEK 8; F. M. SELLMAN.

22 FT Q J P 1 WITNESS INVENTOR:

BY @WflWW wn/ Z?/wa/--- V m I EETORNEYS. E

' N. PETERS. Pmwumo n w. Wilhingmn. D.C.

UNITED STATES PATENT OFFICE."

JOHN GREEK AND FRANCIS M. SELLMAN, OF EVANSVILLE, INDIANA.

EXPANDING ROCK-DRILL.

SPEGIFICATI ON forming part of Letters Patent Nol245,160, dated'Aug'ust2, 1881. Application filed March 31,1881. (ModeL) To all whom it mayconcern Be it known that we, JOHN GREEK and FRANCIS M. SELLMAN, ofEvansville, in the county of Vanderburg and State of Indiana, haveinvented a new and useful Improvement in Expanding Rock-Drills, of whichthe following is a specification.

This invention relates to a means for cutting a recess or cavity at thebottom of a drilled hole in a rock, or a coal or other mine, for thepurpose of receiving the charge of powder or other explosive substanceused in blastmg. i

The invention consists in a novel construction and combination, withadrill rod or holder, of a pair of bits or drills, and the combinationtherewith of a cone of peculiar construction for expanding said bits ordrills, as hereinafter more particularly described.

In the accompanying drawings, Figures 1 and 2 are side views at rightangles to each other, showing the tool in position to be inserted in thedrilled hole. Figs. 3 and 4. show the positions of the bits at twodifferent stages of the work, as hereinafter described.

Similar letters of reference indicate corresponding parts.

A represents the drill rod or holder, which carries at its lower end aferrule, B, within which is a socket for the upper ends of the bits towork in.

.0 represents the bit or drill, which consists of a bar of metalslightly curved and having its ends rounded. When used for coal or softrock the bits may be of steel or case-hardened iron, and when used forhard rock they may be provided with carbon or black-diamond points. Twoof these bits or drills are carried by the drill-stock, so as to swingoutward in opposite directions by means of a pivot, a, passing throughlugs b at the bottom of the ferrule B and through holes in the upper orinner ends of the bits.

As shown in Figs. 1, 2, and 3, the bits are serrated on their ends andon their upper or concave edges, and, as shown in Fig. 4, they areserrated on their loweror convex edges. If desired, they may be serratedon both their upper and lower edges; but in some cases it is preferable'to have two pairs of bits, one

pairserrated on the upper and the other on the lower edges.

D represents a cone, made of iron or steel, and having its base aboutequal to the diameter of the drilled hole in which it is to be used, andbelow said base a shank or stem, (Z, of less diameter. In using thistool, when the drilled hole has reached the desired depth, a smallerhole is drilled in the center of the bottom thereof of sufficient sizeto receive the shank or stem d. The cone D is then placed in the bottomof the drilled hole by means of a wire inserted in a hole, e, in thecenter of the cone, which wire is then withdrawn. The tool is thenlowered into the drilled hole, with the bits in the position shown inFigs. 1 and 2, until said bits reach the top of the cone D, whichexpands them and causes them to cut and drill a recess or cavity, f, ofthe form shown in Fig. 3.

If it is desired to increase the depth of the cavity f, the drill rod orholder is withdrawn and a pair of bits serrated on their convex edgesare substituted for the first pair, as shown in Fig. 4.

We arc aware that it is not broadly new to .employ a cone or wedge tocause lateral divergence of the bits or arms of a boring implement; butin previous inventions in which such elements are combined the cone hasformed an attachment of the boring implement, and the arms have not beenconstructed and arranged to co-operate with the cone, as in ourinvention.

By making the cone separate from the bor in g implement and locating itin the drill-hole, as specified, we attain important advantages inrespect to strength, simplicity, and econ omy of construction of theimplement, and also in the facility with which the cavity may be formedin the earth.

Having thus fully described our invention, we claim as new, and desireto secure by Let ters Patent 1. The combination, as hereinbefore (lescribed, of the detached cone D, adapted to be points diverge laterally,as shown, for the purlaterally, as shown, then simultaneously press posespecified. ing downward. 0n the implement and rotating [0 2. The mode ofcutting a cavity at the botthe same, as shown and described. tom of ahole drilled in the earth, the same JOHN GREEK. 5 consisting in forminga socket for the cone I), FRANCIS M. SELLMAN.

then placing the latter therein, next inserting V'itnesses: in thedrill-hole a boring implement having EDWIN R. HATFIELD,

pivoted arms 0 C, Whose lower ends diverge W'. \V. TILESTON.

